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/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hive.serde2;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import org.apache.hadoop.hive.serde2.ByteStream.RandomAccessOutput;
import org.apache.hadoop.hive.serde2.lazybinary.LazyBinaryUtils;
import org.apache.hadoop.io.WritableUtils;
import org.apache.hive.common.util.HashCodeUtil;
/**
* The structure storing arbitrary amount of data as a set of fixed-size byte buffers.
* Maintains read and write pointers for convenient single-threaded writing/reading.
*/
public final class WriteBuffers implements RandomAccessOutput {
private final ArrayList writeBuffers = new ArrayList(1);
/** Buffer size in writeBuffers */
private final int wbSize;
private final int wbSizeLog2;
private final long offsetMask;
private final long maxSize;
public static class Position {
private byte[] buffer = null;
private int bufferIndex = 0;
private int offset = 0;
public void clear() {
buffer = null;
bufferIndex = offset = -1;
}
}
Position writePos = new Position(); // Position where we'd write
Position unsafeReadPos = new Position(); // Position where we'd read (unsafely at write time).
public WriteBuffers(int wbSize, long maxSize) {
this.wbSize = Integer.bitCount(wbSize) == 1 ? wbSize : Integer.highestOneBit(wbSize);
this.wbSizeLog2 = 31 - Integer.numberOfLeadingZeros(this.wbSize);
this.offsetMask = this.wbSize - 1;
this.maxSize = maxSize;
writePos.bufferIndex = -1;
}
/** THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety). */
public int unsafeReadVInt() {
return (int) readVLong(unsafeReadPos);
}
public int readVInt(Position readPos) {
return (int) readVLong(readPos);
}
/** THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety). */
public long unsafeReadVLong() {
return readVLong(unsafeReadPos);
}
public long readVLong(Position readPos) {
ponderNextBufferToRead(readPos);
byte firstByte = readPos.buffer[readPos.offset++];
int length = (byte) WritableUtils.decodeVIntSize(firstByte) - 1;
if (length == 0) {
return firstByte;
}
long i = 0;
if (isAllInOneReadBuffer(length, readPos)) {
for (int idx = 0; idx < length; idx++) {
i = (i << 8) | (readPos.buffer[readPos.offset + idx] & 0xFF);
}
readPos.offset += length;
} else {
for (int idx = 0; idx < length; idx++) {
i = (i << 8) | (readNextByte(readPos) & 0xFF);
}
}
return (WritableUtils.isNegativeVInt(firstByte) ? (i ^ -1L) : i);
}
/** THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety). */
public void unsafeSkipVLong() {
skipVLong(unsafeReadPos);
}
public void skipVLong(Position readPos) {
ponderNextBufferToRead(readPos);
byte firstByte = readPos.buffer[readPos.offset++];
int length = (byte) WritableUtils.decodeVIntSize(firstByte);
if (length > 1) {
readPos.offset += (length - 1);
}
int diff = readPos.offset - wbSize;
while (diff >= 0) {
++readPos.bufferIndex;
readPos.buffer = writeBuffers.get(readPos.bufferIndex);
readPos.offset = diff;
diff = readPos.offset - wbSize;
}
}
/** THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety). */
public void setUnsafeReadPoint(long offset) {
setReadPoint(offset, unsafeReadPos);
}
public void setReadPoint(long offset, Position readPos) {
readPos.bufferIndex = getBufferIndex(offset);
readPos.buffer = writeBuffers.get(readPos.bufferIndex);
readPos.offset = getOffset(offset);
}
/** THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety). */
public int unsafeHashCode(long offset, int length) {
return hashCode(offset, length, unsafeReadPos);
}
public int hashCode(long offset, int length, Position readPos) {
setReadPoint(offset, readPos);
if (isAllInOneReadBuffer(length, readPos)) {
int result = HashCodeUtil.murmurHash(readPos.buffer, readPos.offset, length);
readPos.offset += length;
return result;
}
// Rare case of buffer boundary. Unfortunately we'd have to copy some bytes.
byte[] bytes = new byte[length];
int destOffset = 0;
while (destOffset < length) {
ponderNextBufferToRead(readPos);
int toRead = Math.min(length - destOffset, wbSize - readPos.offset);
System.arraycopy(readPos.buffer, readPos.offset, bytes, destOffset, toRead);
readPos.offset += toRead;
destOffset += toRead;
}
return HashCodeUtil.murmurHash(bytes, 0, bytes.length);
}
private byte readNextByte(Position readPos) {
// This method is inefficient. It's only used when something crosses buffer boundaries.
ponderNextBufferToRead(readPos);
return readPos.buffer[readPos.offset++];
}
private void ponderNextBufferToRead(Position readPos) {
if (readPos.offset >= wbSize) {
++readPos.bufferIndex;
readPos.buffer = writeBuffers.get(readPos.bufferIndex);
readPos.offset = 0;
}
}
public int hashCode(byte[] key, int offset, int length) {
return HashCodeUtil.murmurHash(key, offset, length);
}
private void setByte(long offset, byte value) {
// No checks, the caller must ensure the offsets are correct.
writeBuffers.get(getBufferIndex(offset))[getOffset(offset)] = value;
}
@Override
public void reserve(int byteCount) {
if (byteCount < 0) throw new AssertionError("byteCount must be non-negative");
int currentWriteOffset = writePos.offset + byteCount;
while (currentWriteOffset > wbSize) {
nextBufferToWrite();
currentWriteOffset -= wbSize;
}
writePos.offset = currentWriteOffset;
}
public void setWritePoint(long offset) {
writePos.bufferIndex = getBufferIndex(offset);
writePos.buffer = writeBuffers.get(writePos.bufferIndex);
writePos.offset = getOffset(offset);
}
@Override
public void write(int b) {
if (writePos.offset == wbSize) {
nextBufferToWrite();
}
writePos.buffer[writePos.offset++] = (byte)b;
}
@Override
public void write(byte[] b) {
write(b, 0, b.length);
}
@Override
public void write(byte[] b, int off, int len) {
if (writePos.bufferIndex == -1) {
nextBufferToWrite();
}
int srcOffset = 0;
while (srcOffset < len) {
int toWrite = Math.min(len - srcOffset, wbSize - writePos.offset);
System.arraycopy(b, srcOffset + off, writePos.buffer, writePos.offset, toWrite);
writePos.offset += toWrite;
srcOffset += toWrite;
if (writePos.offset == wbSize) {
nextBufferToWrite();
}
}
}
@Override
public int getLength() {
return (int)getWritePoint();
}
private int getOffset(long offset) {
return (int)(offset & offsetMask);
}
private int getBufferIndex(long offset) {
return (int)(offset >>> wbSizeLog2);
}
private void nextBufferToWrite() {
if (writePos.bufferIndex == (writeBuffers.size() - 1)) {
if ((1 + writeBuffers.size()) * ((long)wbSize) > maxSize) {
// We could verify precisely at write time, but just do approximate at allocation time.
throw new RuntimeException("Too much memory used by write buffers");
}
writeBuffers.add(new byte[wbSize]);
}
++writePos.bufferIndex;
writePos.buffer = writeBuffers.get(writePos.bufferIndex);
writePos.offset = 0;
}
/** Compares two parts of the buffer with each other. Does not modify readPoint. */
public boolean isEqual(long leftOffset, int leftLength, long rightOffset, int rightLength) {
if (rightLength != leftLength) {
return false;
}
int leftIndex = getBufferIndex(leftOffset), rightIndex = getBufferIndex(rightOffset),
leftFrom = getOffset(leftOffset), rightFrom = getOffset(rightOffset);
byte[] leftBuffer = writeBuffers.get(leftIndex), rightBuffer = writeBuffers.get(rightIndex);
if (leftFrom + leftLength <= wbSize && rightFrom + rightLength <= wbSize) {
for (int i = 0; i < leftLength; ++i) {
if (leftBuffer[leftFrom + i] != rightBuffer[rightFrom + i]) {
return false;
}
}
return true;
}
for (int i = 0; i < leftLength; ++i) {
if (leftFrom == wbSize) {
++leftIndex;
leftBuffer = writeBuffers.get(leftIndex);
leftFrom = 0;
}
if (rightFrom == wbSize) {
++rightIndex;
rightBuffer = writeBuffers.get(rightIndex);
rightFrom = 0;
}
if (leftBuffer[leftFrom++] != rightBuffer[rightFrom++]) {
return false;
}
}
return true;
}
private final boolean isEqual(byte[] left, int leftOffset, int rightIndex, int rightFrom, int length) {
if (length == 0) {
return true;
}
// invariant: rightLength = leftLength
// rightOffset is within the buffers
byte[] rightBuffer = writeBuffers.get(rightIndex);
if (rightFrom + length <= wbSize) {
// TODO: allow using unsafe optionally.
// bounds check first, to trigger bugs whether the first byte matches or not
if (left[leftOffset + length - 1] != rightBuffer[rightFrom + length - 1]) {
return false;
}
for (int i = 0; i < length; ++i) {
if (left[leftOffset + i] != rightBuffer[rightFrom + i]) {
return false;
}
}
return true;
}
for (int i = 0; i < length; ++i) {
if (rightFrom == wbSize) {
++rightIndex;
rightBuffer = writeBuffers.get(rightIndex);
rightFrom = 0;
}
if (left[leftOffset + i] != rightBuffer[rightFrom++]) {
return false;
}
}
return true;
}
/**
* Compares part of the buffer with a part of an external byte array.
* Does not modify readPoint.
*/
public boolean isEqual(byte[] left, int leftLength, long rightOffset, int rightLength) {
if (rightLength != leftLength) {
return false;
}
return isEqual(left, 0, getBufferIndex(rightOffset), getOffset(rightOffset), leftLength);
}
/**
* Compares part of the buffer with a part of an external byte array.
* Does not modify readPoint.
*/
public boolean isEqual(byte[] left, int leftOffset, int leftLength, long rightOffset, int rightLength) {
if (rightLength != leftLength) {
return false;
}
return isEqual(left, leftOffset, getBufferIndex(rightOffset), getOffset(rightOffset), leftLength);
}
/**
* Compares the current readPosition of the buffer with the external byte array.
* Does not modify readPoint.
*/
public boolean isEqual(byte[] left, int leftOffset, Position readPos, int length) {
return isEqual(left, leftOffset, readPos.bufferIndex, readPos.offset, length);
}
public void clear() {
writeBuffers.clear();
clearState();
}
private void clearState() {
writePos.clear();
unsafeReadPos.clear();
}
public long getWritePoint() {
if (writePos.bufferIndex == -1) {
nextBufferToWrite();
}
return ((long)writePos.bufferIndex << wbSizeLog2) + writePos.offset;
}
/** THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety). */
public long getUnsafeReadPoint() {
return getReadPoint(unsafeReadPos);
}
public long getReadPoint(Position readPos) {
return (readPos.bufferIndex * (long)wbSize) + readPos.offset;
}
public void getByteSegmentRefToCurrent(ByteSegmentRef byteSegmentRef, int length,
Position readPos) {
byteSegmentRef.reset((readPos.bufferIndex * (long)wbSize) + readPos.offset, length);
if (length > 0) {
populateValue(byteSegmentRef);
}
}
public void writeVInt(int value) {
LazyBinaryUtils.writeVInt(this, value);
}
public void writeVLong(long value) {
LazyBinaryUtils.writeVLong(this, value);
}
/** Reads some bytes from the buffer and writes them again at current write point. */
public void writeBytes(long offset, int length) {
int readBufIndex = getBufferIndex(offset);
byte[] readBuffer = writeBuffers.get(readBufIndex);
int readBufOffset = getOffset(offset);
int srcOffset = 0;
while (srcOffset < length) {
if (readBufOffset == wbSize) {
++readBufIndex;
readBuffer = writeBuffers.get(readBufIndex);
readBufOffset = 0;
}
if (writePos.offset == wbSize) {
nextBufferToWrite();
}
// How much we can read from current read buffer, out of what we need.
int toRead = Math.min(length - srcOffset, wbSize - readBufOffset);
// How much we can write to current write buffer, out of what we need.
int toWrite = Math.min(toRead, wbSize - writePos.offset);
System.arraycopy(readBuffer, readBufOffset, writePos.buffer, writePos.offset, toWrite);
writePos.offset += toWrite;
readBufOffset += toWrite;
srcOffset += toWrite;
if (toRead > toWrite) {
nextBufferToWrite();
toRead -= toWrite; // Remains to copy from current read buffer. Less than wbSize by def.
System.arraycopy(readBuffer, readBufOffset, writePos.buffer, writePos.offset, toRead);
writePos.offset += toRead;
readBufOffset += toRead;
srcOffset += toRead;
}
}
}
/**
* The class representing a segment of bytes in the buffer. Can either be a reference
* to a segment of the whole WriteBuffers (when bytes is not set), or to a segment of
* some byte array (when bytes is set).
*/
public static class ByteSegmentRef {
public ByteSegmentRef(long offset, int length) {
reset(offset, length);
}
public void reset(long offset, int length) {
if (length < 0) {
throw new AssertionError("Length is negative: " + length);
}
this.offset = offset;
this.length = length;
}
public ByteSegmentRef() {
}
public byte[] getBytes() {
return bytes;
}
public long getOffset() {
return offset;
}
public int getLength() {
return length;
}
public ByteBuffer copy() {
byte[] copy = new byte[length];
if (length > 0) {
System.arraycopy(bytes, (int)offset, copy, 0, length);
}
return ByteBuffer.wrap(copy);
}
private byte[] bytes = null;
private long offset;
private int length;
}
/**
* Changes the byte segment reference from being a reference to global buffer to
* the one with a self-contained byte array. The byte array will either be one of
* the internal ones, or a copy of data if the original reference pointed to a data
* spanning multiple internal buffers.
*/
public void populateValue(WriteBuffers.ByteSegmentRef value) {
// At this point, we are going to make a copy if needed to avoid array boundaries.
int index = getBufferIndex(value.getOffset());
byte[] buffer = writeBuffers.get(index);
int bufferOffset = getOffset(value.getOffset());
int length = value.getLength();
if (bufferOffset + length <= wbSize) {
// Common case - the segment is in one buffer.
value.bytes = buffer;
value.offset = bufferOffset;
return;
}
// Special case (rare) - the segment is on buffer boundary.
value.bytes = new byte[length];
value.offset = 0;
int destOffset = 0;
while (destOffset < length) {
if (destOffset > 0) {
buffer = writeBuffers.get(++index);
bufferOffset = 0;
}
int toCopy = Math.min(length - destOffset, wbSize - bufferOffset);
System.arraycopy(buffer, bufferOffset, value.bytes, destOffset, toCopy);
destOffset += toCopy;
}
}
private boolean isAllInOneReadBuffer(int length, Position readPos) {
return readPos.offset + length <= wbSize;
}
private boolean isAllInOneWriteBuffer(int length) {
return writePos.offset + length <= wbSize;
}
public void seal() {
if (writePos.bufferIndex == -1) {
return;
}
if (writePos.offset < (wbSize * 0.8)) { // arbitrary
byte[] smallerBuffer = new byte[writePos.offset];
System.arraycopy(writePos.buffer, 0, smallerBuffer, 0, writePos.offset);
writeBuffers.set(writePos.bufferIndex, smallerBuffer);
}
if (writePos.bufferIndex + 1 < writeBuffers.size()) {
writeBuffers.subList(writePos.bufferIndex + 1, writeBuffers.size()).clear();
}
// Make sure we don't reference any old buffer.
clearState();
}
/** THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety). */
public long unsafeReadNByteLong(long offset, int bytes) {
return readNByteLong(offset, bytes, unsafeReadPos);
}
public long readNByteLong(long offset, int bytes, Position readPos) {
setReadPoint(offset, readPos);
long v = 0;
if (isAllInOneReadBuffer(bytes, readPos)) {
for (int i = 0; i < bytes; ++i) {
v = (v << 8) + (readPos.buffer[readPos.offset + i] & 0xff);
}
readPos.offset += bytes;
} else {
for (int i = 0; i < bytes; ++i) {
v = (v << 8) + (readNextByte(readPos) & 0xff);
}
}
return v;
}
public void writeFiveByteULong(long offset, long v) {
int prevIndex = writePos.bufferIndex, prevOffset = writePos.offset;
setWritePoint(offset);
if (isAllInOneWriteBuffer(5)) {
writePos.buffer[writePos.offset] = (byte)(v >>> 32);
writePos.buffer[writePos.offset + 1] = (byte)(v >>> 24);
writePos.buffer[writePos.offset + 2] = (byte)(v >>> 16);
writePos.buffer[writePos.offset + 3] = (byte)(v >>> 8);
writePos.buffer[writePos.offset + 4] = (byte)(v);
writePos.offset += 5;
} else {
setByte(offset++, (byte)(v >>> 32));
setByte(offset++, (byte)(v >>> 24));
setByte(offset++, (byte)(v >>> 16));
setByte(offset++, (byte)(v >>> 8));
setByte(offset, (byte)(v));
}
writePos.bufferIndex = prevIndex;
writePos.buffer = writeBuffers.get(writePos.bufferIndex);
writePos.offset = prevOffset;
}
public int readInt(long offset) {
return (int)unsafeReadNByteLong(offset, 4);
}
@Override
public void writeInt(long offset, int v) {
int prevIndex = writePos.bufferIndex, prevOffset = writePos.offset;
setWritePoint(offset);
if (isAllInOneWriteBuffer(4)) {
writePos.buffer[writePos.offset] = (byte)(v >> 24);
writePos.buffer[writePos.offset + 1] = (byte)(v >> 16);
writePos.buffer[writePos.offset + 2] = (byte)(v >> 8);
writePos.buffer[writePos.offset + 3] = (byte)(v);
writePos.offset += 4;
} else {
setByte(offset++, (byte)(v >>> 24));
setByte(offset++, (byte)(v >>> 16));
setByte(offset++, (byte)(v >>> 8));
setByte(offset, (byte)(v));
}
writePos.bufferIndex = prevIndex;
writePos.buffer = writeBuffers.get(writePos.bufferIndex);
writePos.offset = prevOffset;
}
@Override
public void writeByte(long offset, byte value) {
int prevIndex = writePos.bufferIndex, prevOffset = writePos.offset;
setWritePoint(offset);
// One byte is always available for writing.
writePos.buffer[writePos.offset] = value;
writePos.bufferIndex = prevIndex;
writePos.buffer = writeBuffers.get(writePos.bufferIndex);
writePos.offset = prevOffset;
}
/**
* Write buffer size
* @return write buffer size
*/
public long size() {
return writeBuffers.size() * (long) wbSize;
}
/** THIS METHOD IS NOT THREAD-SAFE. Use only at load time (or be mindful of thread safety). */
public Position getUnsafeReadPosition() {
return unsafeReadPos;
}
}
